The disclosure relates to gas turbine engine manufacture. More particularly, the disclosure relates to spray masking for rotors of gas turbine engines.
In gas turbine engines, many components are subject to spray coating of thermal barrier coatings (TBCs), other environmental coatings, and associated bond coats. A number of situations involving gas turbine engine rotors involve applying a coating to an annular surface portion of the rotor while masking an adjacent portion. Examples of such situations involve portions of disks, disk spacers, hubs, and the like. One particular example involves the masking of integrally bladed rotors. One example of an integrally bladed rotor (IBR) involves a single blade stage of a compressor or turbine section of a gas turbine engine. A more particular example is a single high pressure compressor (HPC) stage comprising a disk extending from an inner aperture to an outer rim. A circumferential array of blades protrudes radially from the rim to associated blade tips. Such a disk may be formed via a powder metallurgy process (e.g., of a nickel-based superalloy or a cobalt-based superalloy). The exemplary disk may be forged to near net shape and then subject to machining. An exemplary ultimate configuration involves applying a protective coating away from the airfoils but leaving the airfoils bare. In one such example of such a configuration, the airfoils are super-polished. The airfoils and adjacent areas of disks (e.g., the inter-airfoil spaces on the disk rim) are masked off to allow coating to be applied to remaining portions of the disks.
United States Patent Application Publications 20130136864 A1 of Strock, et al., published May 30, 2013 and entitled “PASSIVE TEMPERATURE CONTROL OF HPC ROTOR COATING” ('864 publication) and 20120132138 A1 of Beaudoin, et al., published May 31, 2012 and entitled “DIMENSIONALLY STABLE DURABLE THERMAL SPRAY MASKING SYSTEM” (the '138 publication) disclose masking systems and methods for such turbine engine rotor components.